Circulating air heating furnace with internal air heating conduit



July 28, 1953 E. F. FROMME CIRCULATING AIR HEATING FURNACE WITH INTERNAL AIR HEATING CONDUIT Filed Aug. 1, 1950 17 11 .Ziq'gni LJ L 2: a E g a INVENTOR. I954. .ZZF'floMME Patented July 28, 1953 UNITED sTATEs "PATENT 2,646,791 OFFICE CIRCULATING AIR HEATING FURNACE WITH INTERNAL AIR HEATIN G CONDUIT Earl F. Fromme, Kirksville, Mo.

Application August 1, 1950, Serial No. 177,099

3 Claims. '1

This invention relates to an improved circulating air heater, especially, but not exclusively, of the oil or gas-fired type, and the primary object of the invention is to provide a more efficient and practical heater of this kind which utilizes a greater proportion of the heat generated by the heating element, and which enables better control and distribution of the hot air discharged by the heater into a room or other space to be heated, whereby increased heating efficiency is obtained compared to other air heaters of similar capacity.

Another important object of the invention is to provide an air heater of the character indicated above in which the intake of cool air and the circulation within the heater of both the intaken cool air and the hot air heated therein and the output of the hot air from the heater are produced by a single blower.

A further important object of the invention is to provide a compact and relatively inexpensive air heater of the character indicated above in which the intaken cool air is circulated initially in contact with the outside of a barrel heated by and surrounding a conduit serving as a flame spreader, against which flame from the heating element plays, whence a portion of the thus initially heated air passes through the flame spreader'conduit to be highly heated therein, the resultant highly heated air then passing from the flame spreader conduit along and in contact with the outside of the barrel toward the output of the heater, a portion of the initially heated air not passing through the flame spreader conduit being arranged to be introduced into the stream of the highly heated air as the latter passes in contact with the outside of the barrel on its way to the heater output.

A still further important object of the invention is to provide an air heater of the character indicated above wherein the cool air intake means and the heated air output means are in a base at floor level, whereby circulation of heated air within a room from floor to ceiling can be obtained to provide a uniform temperature from floor to ceiling.

Other important objects and advantageous features of the invention will be apparent from the following description and the accompanying drawings, wherein, for purposes of illustration only, a specific embodiment of the invention set forth in detail.

, In the drawings, wherein like numerals designate like parts throughout the several views:

Figure 1 is a transverse vertical section taken on the line |-l of Figure 2;

Figure 2 is a top plan view with the outer casing removed, certain internal structure being shown in dotted lines;

Figure 3 is a fragmentary, left-hand side elevation of Figure 2, partly broken away, to show internal structure;

Figures 4 and 5 are horizontal sections taken on the lines 4-4 and 5-5, respectively, of Figure 1, the casing being removed.

Referring in detail to the drawings, the illustrated air heater comprises a hollow substantially square, relatively flat or shallow base I having a bottom wall 8, a top wall 9 and side walls ll] connecting the outer edges of the bottom and top walls. Within the base I at one side thereof, in the case of use of an oil burner as the heating element, is a generally triangular oil sump ll having a drain pipe l2 at one corner thereof depending through the bottom wall 8.. Positioned within the oil sump H is a conventional form of carburetor 13 having suitable connection (not shown) to an oil burner I 4. The oil burner 14 is mounted on and rises above the base top wall 9 somewhat forwardly of center position, as indicated in dotted lines in Figure 2.

The interior of the base I is divided into a rear cool air chamber or space It and a forward heated air chamber or space I 6 by a partition or wall ll extending across the interior of the base between the sides thereof. As indicated in Figures 2 and 3, the wall I! may have one end thereof connected to the wall H of the sump II, in which case the sump acts as a part of the partition ll. As shown in Fig. 2, the rear side wall of the base 1 has a cool air inlet [8 near the right-hand end thereof, and the left-hand side wall has another cool air inlet l9 near the rear end thereof, both inlets communicating exclusively with the cool air chamber l5. The front base side wall has left and right-hand heated air outlets 2t and 2|, respectively, near the left and right-hand ends thereof; and a third heated air outlet 22 on the forward end part of the left-hand base side wall, all of the outlets 28, 2! and Z2 communicating exclusively with the heated air chamber 16. Thevarious inlets and outlets are in the form of screened ports with which suitable air flow-controlling means (not shown) can be readily associated to afiord accurate control of air circulation. A removable casing 23, of vertically elongated, rectangular form, is adapted to rest its lower end on the base 1 and enclose the upper surface of the top wall 9 thereof, and be secured in position by suitable means (not shown). The casing 23 has a top wall wall 24 provided with a flue opening 25, and side walls 26 provided at vertical intervals with perforations or gratings 21 providing for a certain amount of direct convection heating of room air outside of the heater casing.

Rising from the base top wall 59 around the burner or fire pot I 4 is the tubular, cylindrical inner or heating barrel 28, which is closed at its lower end, as indicated at 29, and has a closed horizontal upper end. An eccentric flue pipe 3! rises from the upper end 30 and extends through the flue opening 28 in the casing top "wall 24 approximately centrally of the casing 23.

rel 28.

The upper end 30 of the barrel 28 is spaced downwardly from the casing top wall 24, as shown in Figure 1. The lower end 29 of the barrel 28 is provided with a dependin updraft pipe 32 through which combustion air from a suitable source (not shown) rises through the barrel 28, feeds the burner f4, and carries the flame and products of combustion upwardly in the barrel and out through the flue pipe 3| to a place outside of the room in which the heater 1 is located.

Supported in concentrically spaced relation within the upper part of the barrel 28 and in spaced relation above its burner Hi is the airheating conduit 33 which includes an inverted hollow frus'to-conical burner flame-spreader 3t and a helical, tubular heating coil 35 above the flame-spreader. The lower end of the coil 35 has a laterally offset, depending portion 36 connected to one side of the top of the spreader 3 and communicating with the interior of the spreader. The opposite side of the top of the spreader 3' has a lateral tubular part 3; extending to and opening through the side wall 33 of the barrel 23, as a port 39 located interme diate the upper and lower ends of the bar- The upper end of the coil 85 has a 4 air duct 54 in the offset 41 on the opposite side of the ba'file plate 5| is closed by the top wall 9 of the base 1.

As a result of the foregoing structure, the space between the inner and outer barrels 28 and 45, respectively, is in open and direct communication with the cool air duct 54 and the hot air duct 56.

A preferably push-pull type of electric blower G0 hasits housing 6| mounted on the top wall 9 of the base 1 to the rear and to the right of the outer barrel 45 and has its tangential output pipe 62 extended forwardly to the rear side wall 58, of the offset 47, through which the pipe 52 opens. The intake side of the blower 5B is in communication with the cool air chamber l5 of the base I through an opening 63 provided in the base top wall '9. A cleanout housing 59 extends through and beyond the front side wall 46 of the outer barrel 45 and is secured to the inner barrel 23 for easy access to the interior of the inner barrel 2S and is sealed against escape of air when-closed. A strip 59 surrounding the housing 58 extends between and is secured to both the inner barrel 23 and the outer barrel 4'5 for reinforcement thereof.

laterally directed portion ie reaching to and i.

opening through the barrel side wall 38 as a port 4!, located close to its upper end baffle plate "42 formed with perforations is positioned between the uppermost and the next lower convolutions of the coil 35, to retard the upward passage of hot products of combustion through the coil and thereby obtain a greater heat transfer to the coil 35.

concentrically spaced around the barrel 28, as

indicated in Figures 2, 4 and 5, is the tubular,

cylindrical outer barrel 45 which rises from the top wall 9 of the base I. The left-hand side of the side wall 45 of the outer barrel 65 as seen in the drawings is provided with a radial offset il of rectangular, horizontal cross-section which has plane front and rear side walls 58 and 58, respectively, joined to the outer barrel side wall 48, and a plane outer wall 49 joining the outer ends of the side walls 48 and 48, as shown in Figures 2, 4 and 5. The offset il extends from ward edge secured to the outer wall it of the.

ofiset 41 and is parallel to and equally spaced from the offset side walls 48 and G8. The baffle plate 5| reaches to the outer cylinder G5 and has its radially inward edge secured to the adjacent part of the side wall 38 of the inner barrel '28. The upper end of the bafile plate 55 has an extension 52 which reaches across the upper end 30 of the inner barrel 28, and extends vertically between the upper end 30 and the top 58 of the outer barrel G5. The extension 52 reaches only about one-third of the distance across the top 30 of the inner barrel 28; The lower end of the hot air duct 55 of the offset ii defined by the rear side wall it, the outer wall cc, and the baffle plate 5!, is open, as indicated at 55, to the interior of the hot air chamber it within the base 1, but the lower end of the companion cool In operation, the burner l6 and the blower 69 being in operation, 'c'ool room air is drawn from a level near the floor into the cool air chamber [5 of the base i through the inlets l8 and I9 and forced upwardly in the cool air duct 5.; of the offset 3? and around the adjacent side of the inner barrel 28. As the cool air rises in contact with the outside of the inner barrel the air i initially heated thereby. As the initially heated air rises in the duct 56 toward the top 50 of the outer barrel 45, part thereof passes through the port 5! and flows downwardly through coil 35 and name-spreader 3'4, thereby being heated to the highest degree. The port with which the flame-spreader 35 connects being in communication only with the hot air duct 5 3, the highly heated air passing downwardly through the coil 35 and spreader 34 passes downwardly therein and through the base top opening 5i: into the hot or heated air chamber in the forward part of the base i, from which the hot air escapes through the outlets 29, 2| and 22 intothe room at floor level. In the rise of the initially heated air toward the upper ends of the inner barrel 2B and outer barrel 45, such of this air as does not pass through the port til into the heating conduit 33 passes around the inner barrel E3 and over the top of the inner barrel along the adjacent side of the bafiie plate extension 52 and flue pipe 31 and upon reaching the opposite side of the inner barrel 28, joins the downward circulation of heated air in the hot air conduit 53, the circulation of heated air around the inner barrel being in a counterclockwise direction.

It will be seen from the foregoing that there is a ccntinuousfiow of air through the heater while the blower 60 is in operation, and that with the burner I4 also in operation, there are several stages of desirable heat exchange, both conductive and convective, between hot portions of the heater and the circulating air and between heated portions of the circulating air and cooler portions of the circulating air, whereby the air outputted from the heater is at a higher temperature and in greater volume than is the case with other heaters of similar capacity.

I claim:

1. In an air-circulating heater, a closed hollow base, partition means dividing the interior of said base into a cool air chamber and a heated air chamber, air inlet means for said cool air chamber, outlet means for said heated air chamber, an inner tubular heating barrel mounted upon said base and having its lower end closed by a portion on said base, a burner within the lower end of said heating barrel, a restricted combustion air inlet leading into the lower end of said inner barrel, said inner barrel having a closed upper end, a restricted flue pipe leading from the upper end of said inner barrel, an outer barrel having a lower end mounted upon and closed by said base, said outer barrel spacedly surrounding said inner barrel and having a closed upper end spaced above the upper end of said inner barrel, the space between said inner and outer barrels forming an air heating space, a bafiie extending from said base to the closed upper end of the outer barrel and reaching across the space between the inner and outer barrels on one side thereof only whereby the air heating space provides a U-shaped passageway extending around the inner barrel, an air heating conduit within said inner barrel and located above and in heat exchange relation to said burner, said conduit having an end leading from the inner barrel into said space at one side of said bafile and having another end opening into said space at the opposite side of said baille,

means providing communication between said heated air chamber and said air heating space at one side of and adjacent said bafiie, a blower having an intake communicating with said cool air chamber and an outlet communicating with said air heating space at the other sideof and adjacent the baffle whereby cool air is indrawn into said cool air chamber through said inlet means and is discharged into said space to circulate around the inner and outer barrels and move from said hot air space into the hot air chamber of the base and discharge therefrom through said outlet means.

2. In an air-circulating heater, a closed hollow base, partition means dividing the interior of said base into a cool air chamber and a heated air chamber, air inlet means for said cool air chamber, outlet means for said heated air chamher, an inner tubular heating barrel mounted upon said base and having its lower end closed by a portion on said base, a burner within the lower end of said heating barrel, a restricted combustion air inlet leading into the lower end of said inner barrel, said inner barrel having a closed upper end, a restricted flue pipe leading from the upper end of said inner barrel, an outer barrel having a lower end mounted upon and closed by said base, said outer barrel spacedly surrounding said inner barrel and having a closed upper end spaced above the upper end of said inner barrel, the space between said inner and outer barrels forming an air heating space, a baffle extending from said base to the closed upper end of the outer barrel and reaching across the space between the inner and outer barrels on one side thereof only whereby "the air heating space provides a U-shaped passageway extending around the inner barrel, an air heating conduit within said inner barrel and located above and in heat exchange relation to said burner, said conduit having an end leading from the inner barrel into said space at one side of said baflie and having another end opening into said space at the opposite side of said baffle, means providing communication between said heated air chamber and said air heating space at one side of and adjacent said baiile, a blower having an intake communicating with said cool air chamber and an outlet communicating with said air heating space at the other side of and adjacent the baflie whereby cool air is indrawn into said cool air chamber through said inlet means and is discharged into said space to circulate around the inner and outer barrels and move from said hot air space into the hot air chamber of the base and discharge therefrom through said outlet means, the said ends of said air heating conduit being in substantially vertically spaced relation to each other.

3. In an air-circulating heater, a closed hollow base, partition means dividing the interior of said base into a cool air chamber and a heated air chamber, air inlet means for said cool air chamber, outlet means for said heated air chamher, an inner tubular heating barrel mounted upon said base and having its lower end closed by a portion on said base, a burner within the lower end of said heating barrel, a restricted combustion air inlet leading into the lower end of said inner barrel, said inner barrel having a closed upper end, a restricted flue pipe leading from the upper end of said inner barrel, an outer barrel having a lower end mounted upon and closed by said base, said outer barrel spacedly surrounding said inner barrel and having a closed upper end spaced above the upper end of said inner barrel, the space between said inner and outer barrels forming an air heating space, a baflle extending from said base to the closed upper end of the outer barrel and reaching vertically across the space between the inner and outer barrels on one side thereof only whereby the air heating space provides a U-shaped passageway extending around the inner barrel, an air heating conduit within said inner barrel and located above and in heat exchange relation to said burner, said conduit having an end leading from the inner barrel into said space at one side of said bafile and having another end opening into said space at the opposite side of said baflle, means providing communication between said heated air chamber and said air heating space at one side of and adjacent said baiiie, a blower having an intake communicating with said cool air chamber and an outlet communicating with said air heating space at the other side of and adjacent the bafiie whereby cool air is indrawn into said cool air chamber through said inlet means and is discharged into said space to circulate around the inner and outer barrels and move from said hot air space into the hot air chamber of the base and discharge therefrom through said outlet means, said baffie including a portion on the upper end thereof extending across the space between the upper end of the inner barrel and the upper end of the outer barrel.

EARL F. FROMME.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 281,795 Ridgway July 24, 1883 1,356,147 I-Iillyer Oct. 19, 1920 2,022,333 Woolley Nov. 26, 1935 2,073,424 LaFay Mar. 9, 1937 2,212,222 Austin Aug. 20, 1940 2,382,800 Logue Aug. 14, 1945 2,457,813 Heiman Jan. 4, 1949 

